The present invention relates generally to embroidery and more particularly to methods and systems for converting an image to a color-reduced image having colors corresponding to a set of available embroidery thread colors.
Embroidery is the art of applying decorative threaded designs to fabric or textiles. In machine embroidery, embroidery designs are stitched with an automated embroidery machine that holds a limited number of thread spools and stitches a design using a number of thread colors as limited by the number of thread spools. Embroidery designs are digitized into a sequence of embroidery primitives with embroidery software, and then converted to individual stitches using a stitch engine. Methods, systems, and techniques for computer-assisted embroidery are described in U.S. Pat. No. 6,836,695 to Goldman, U.S. Pat. No. 7,016,756 to Goldman, U.S. Pat. No. 6,947,808 to Goldman, U.S. Pat. No. 7,016,757 to Goldman, U.S. Pat. No. 7,587,256 to Goldman, U.S. Pat. No. 6,804,573 to Goldman, U.S. Pat. No. 6,397,120 to Goldman, U.S. Patent Application Publication No. US 2010-0191364 A1 to Goldman, U.S. Patent Application Publication No. US 2007-0118245 A1 to Goldman et al., U.S. Patent Application Publication No. US 2010-0017011 A1 to Goldman et al., U.S. Patent Application Publication No. US 2008-0079727 A1 to Goldman et al., U.S. patent application Ser. No. 12/969,359 to Goldman et al., U.S. patent application Ser. No. 12/911,521 to Hsu et al., U.S. patent application Ser. No. 13/017,945 to Nykyforov, and U.S. patent application Ser. No. 13/019,222 to Benitez et al., each of which is incorporated by reference herein for all that they teach.
Embroidered products may be viewed and purchased at various websites accessible through the Internet. Most embroidery vendors offer a number of different embroidery designs that have been previously prepared by an embroidery designer to be suitable for embroidery. At least one vendor allows a user to upload an image and have it converted to an embroidery design. U.S. Patent Application Publication US2010/010,6283 A1, hereby incorporated by reference herein for all that it teaches, describes an embroidery system and method in which a consumer can provide a design, such as images or text, have it converted into a digitized image and then used to generate customized embroidery that can be placed onto a product.
Not all images are suitable for embroidery. Images best suited to embroidery are those containing only a few colors and which can be represented using simple shapes of solid color. Images with too many colors or which contain complicated or small detail do not translate well to embroidery. Furthermore, since an image may contain millions of different colors, the number of colors must be reduced to a small set of colors which correspond to a set of available thread colors. Furthermore, since a given embroidery machine may only allow stitching from a limited number of thread spools, the number of colors in the image may need to be further reduced to a number equal to or less than the limited number of thread spools held by the particular embroidery machine.
Color reduction of an image is essentially a form of downsampling the image to a few discrete colors, and as known by those in the art, downsampling of an image can change the appearance of the image, and depending on the image, can negatively affect the aesthetics of the image. For example, new edges may appear in the color-reduced image which appeared as a gradual transition of color in the original image. Conversely, edges which appear in the original image may disappear as original colors are mapped to the same discrete color in the color-reduced image.
While color-reduction processes exist, known color-reduction processes reduce the colors to the dominant colors in the image (i.e., those colors covering the most pixels) and without regard to actual thread colors used in embroidery. Thus, important but small detail of some images may become completely lost after color-reduction takes place. Furthermore, there is no guarantee that the resulting color-reduced image contains colors that match available thread colors. Color reduction is performed without regard to the end application—conversion of the image to an embroidery design that will be embroidered using actual embroidery thread colors.
In the past, the judgment of whether or not an image lends itself well to embroidery and the mapping of image colors to embroidery thread colors has been left to humans with a trained eye for the types of images that will look good when translated into an embroidered image. However, with the advent of online vendors offering embroidered products, it would be desirable to allow a user to upload an image, have it converted to an embroidery design, and order a product embroidered with the design. To avoid customer disappointment, it would further be desirable to automatically color-reduce the uploaded image, and present to the user one or more proposed color-reduced embroidery designs from which the user can select so that the user will understand how the image will appear when embroidered prior to ordering the product.